<?php
/**
 * CDbColumnSchema class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2011 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CDbColumnSchema class describes the column meta data of a database table.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: CDbColumnSchema.php 3099 2011-03-19 01:26:47Z qiang.xue $
 * @package system.db.schema
 * @since 1.0
 */
class CDbColumnSchema extends CComponent
{
    /**
     * @var string name of this column (without quotes).
     */
    public $name;
    /**
     * @var string raw name of this column. This is the quoted name that can be used in SQL queries.
     */
    public $rawName;
    /**
     * @var boolean whether this column can be null.
     */
    public $allowNull;
    /**
     * @var string the DB type of this column.
     */
    public $dbType;
    /**
     * @var string the PHP type of this column.
     */
    public $type;
    /**
     * @var mixed default value of this column
     */
    public $defaultValue;
    /**
     * @var integer size of the column.
     */
    public $size;
    /**
     * @var integer precision of the column data, if it is numeric.
     */
    public $precision;
    /**
     * @var integer scale of the column data, if it is numeric.
     */
    public $scale;
    /**
     * @var boolean whether this column is a primary key
     */
    public $isPrimaryKey;
    /**
     * @var boolean whether this column is a foreign key
     */
    public $isForeignKey;
    /**
     * @var boolean whether this column is auto-incremental
     * @since 1.1.7
     */
    public $autoIncrement=false;


    /**
     * Initializes the column with its DB type and default value.
     * This sets up the column's PHP type, size, precision, scale as well as default value.
     * @param string $dbType the column's DB type
     * @param mixed $defaultValue the default value
     */
    public function init($dbType, $defaultValue)
    {
        $this->dbType=$dbType;
        $this->extractType($dbType);
        $this->extractLimit($dbType);
        if($defaultValue!==null)
        $this->extractDefault($defaultValue);
    }

    /**
     * Extracts the PHP type from DB type.
     * @param string $dbType DB type
     */
    protected function extractType($dbType)
    {
        if(stripos($dbType,'int')!==false && stripos($dbType,'unsigned int')===false)
        $this->type='integer';
        else if(stripos($dbType,'bool')!==false)
        $this->type='boolean';
        else if(preg_match('/(real|floa|doub)/i',$dbType))
        $this->type='double';
        else
        $this->type='string';
    }

    /**
     * Extracts size, precision and scale information from column's DB type.
     * @param string $dbType the column's DB type
     */
    protected function extractLimit($dbType)
    {
        if(strpos($dbType,'(') && preg_match('/\((.*)\)/',$dbType,$matches))
        {
            $values=explode(',',$matches[1]);
            $this->size=$this->precision=(int)$values[0];
            if(isset($values[1]))
            $this->scale=(int)$values[1];
        }
    }

    /**
     * Extracts the default value for the column.
     * The value is typecasted to correct PHP type.
     * @param mixed $defaultValue the default value obtained from metadata
     */
    protected function extractDefault($defaultValue)
    {
        $this->defaultValue=$this->typecast($defaultValue);
    }

    /**
     * Converts the input value to the type that this column is of.
     * @param mixed $value input value
     * @return mixed converted value
     */
    public function typecast($value)
    {
        if(gettype($value)===$this->type || $value===null || $value instanceof CDbExpression)
        return $value;
        if($value==='')
        return $this->type==='string' ? '' : null;
        switch($this->type)
        {
            case 'string': return (string)$value;
            case 'integer': return (integer)$value;
            case 'boolean': return (boolean)$value;
            case 'double':
            default: return $value;
        }
    }
}
